Allegro MicroSystems has launched MOSFET gate driver IC to drive high-voltage MOSFETs controlling power input to brushless DC motors used in hybrid, electric cars/vehicles. The 600V MOSFET supporting gate driver IC is also suggested for 48 V automotive battery systems such as electronic power steering, A/C compressors, fans, pumps and blowers. The A4900 is also offered in a non-automotive version for high voltage industrial and commercial applications.
A4900 features six gate drives to drive N-channel IGBT or power MOSFET switches. The gate drives are configured as three high-voltage high-side drives and three low-side drives. The high-side drives are isolated up to 600 V to allow operation with high bridge (motor) supply voltages. Highside drives use a bootstrap capacitor to provide greater than the supply gate drive voltage needed for N-channel FET’s. Each FET can be controlled with a TTL logic level input compatible with 3.3 V or 5 V logic systems.
A single supply input provides the gate drive supply and the bootstrap capacitor charge source. An internal regulator from the single supply provides the lower internal voltage for the logic circuit. The A4900 provides internal monitors to ensure that the gate-source voltage of both high-side and low-side external FET above 9 V when active.
Each driver of A4900 can be driven with an independent PWM signal allowing implementation of all motor excitation methods including trapezoidal and sinusoidal drive. Integrated diagnostics provide indication of under voltage, over temperature and power bridge faults that can be configured to protect the power switches under most short circuit conditions. Detailed diagnostics are available as a serial data word.
The A4900KLQTR-T is supplied in a 44 lead QSOP (suffix ‘LQ’) package.